Way to Heaven

You found a guard right between Heaven and Hell ( you don't know which is which). He is from one of them and you don't know which of them he is from. If he is from Hell, he always lies and if he is from Heaven, he always speaks truth.
You got to find out heaven asking him only one question.

Ask him whether he is a male or a female ..if he says female ..then you can confirm that he is from the hell and u may know the which is whcih ....if he's from heaven he would say "im a male" and subsequently u would know which is which... ;)